Drug Interaction Report

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of tolvaptan, which is primarily metabolized by the isoenzyme. When tolvaptan was administered with the potent CYP450 3A4 inducer rifampin, tolvaptan peak plasma concentration (Cmax) and systemic exposure (AUC) decreased by approximately 85%. The interaction has not been studied with other, less potent inducers.

MANAGEMENT: The potential for diminished pharmacologic effects of tolvaptan should be considered during coadministration with CYP450 3A4 inducers. Alternative treatments may be required if an interaction is suspected.

You should avoid drinking grapefruit juice during treatment with tolvaptan. Grapefruit juice can cause too much of the medication to be in the blood. Serious nervous system side effects such as difficulty swallowing, trouble speaking, muscle weakness, trouble controlling body movements, confusion, mood changes, seizures, and coma may occur. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.